Method and device for regulation or control of a restraint system in a vehicle

ABSTRACT

A method and a device for control or regulation of a restraint system in a vehicle having a safety belt and at least one of an operation or convenience function. The operation and convenience functions of the restraint system adapt in a situation-related fashion and set the belt retraction force that acts on the safety belt.

This application is a national stage of PCT International ApplicationNo. PCT/EP2005/008674, filed Aug. 10, 2005.

BACKGROUND AND SUMMARY OF THE INVENTION

The invention relates to a method and a device for regulation or controlof a restraint system in a vehicle having a safety belt and an operationor convenience function. The belt retraction force acting on the safetybelt is set in a situation-related fashion. That is, the operation andconvenience functions adapt to a situation by increasing or decreasingthe force.

Seat belt systems with belt pretensioners that use a motor to tension arestoring spring as a function of parameter for returning the safetybelt are generally known. Such systems with belt pretensioners aredisclosed, for example, in DE 102 04 475 A1, DE 102 04 476 A1, DE 102 04477 A1 and DE 101 58 871 A1.

Further methods are known for the continuous adaptation of the beltretraction force. DE 103 10 069 A1 discloses determining measured valuesfor the tensile forces acting on the belt band, e.g., force measuringsignals during normal driving operation, during a pre-crash phase orduring an accident, and using them for regulation or control of therestraint system.

DE 196 36 448 C2 discloses determining the position of the driver's ownvehicle relative to an object detected in the vicinity of the vehicle,and controlling a belt tension control mechanism as a function of theproximity of the object relative to the driver's own vehicle. In thiscase, the belt tension control mechanism is used to hold the safety beltin a predetermined number of modes with different prescribed belttension values.

One object of the invention is to specify a method and a device forcontrol or regulation of a restraint system in a vehicle that, inaddition to security, enables operational convenience for the restraintsystem.

This and other objects are achieved in a restraint system for apassenger of a vehicle in that at least one operation, safety orconvenience function is set on the restraint system by adapting in asituation-related fashion a belt retraction force acting on the safetybelt. The belt retraction force or belt restraint force is understood,in particular, as the tensile force acting on the safety belt when thesafety belt is donned (put on) or taken off. In this case, increasingthe belt retraction force increases the tension of the safety belt;while a reduction in the belt retraction force effects a loosening ofthe belt. An operation function of the restraint system is understood,in particular, as the support of the occupant when donning and takingoff the safety belt, for example through a loosening or tensioning ofthe safety belt. A safety function of the restraint system isunderstood, in particular, as the restraining of an occupant that isrequired in a critical situation and is supplied by the safety belt, andthus a strong tensioning of the safety belt. A convenience function isunderstood, in particular, as the setting of an individual wearing levelon the safety belt.

The advantage of the invention consists in that an improved conveniencefunction, safety function or operation function of the safety belt isenabled by setting the safety belt particularly in a fashion that iscontinuous and adapted to the respective vehicle situation orsurrounding situation. To this end, both the instantaneous operatingsituation of the driver's own vehicle, and the surroundings of thevehicle are determined such that upon determination of the situation anappropriate belt retraction force is set, for example, upon fastening orunfastening the belt. The vehicle occupant is restrained in a wayadapted to the instantaneous situation, or the vehicle occupant issupported when donning or taking off the safety belt. This leads to asubstantial improvement in and enhancement of convenience in beltwearing, belt safety and belt operation.

To improve convenience in belt operation, the belt retraction force isreduced to a prescribed belt donning value upon unlocking the vehicle orupon actuating a central locking system of the vehicle. By reducing thebelt retraction force as early as when unlocking the vehicle, thevehicle occupant is supported when subsequently donning the safety beltby virtue of the fact that the safety belt can be more easilymanipulated and donned because of the lowering of the force to a definedlevel of operational convenience. The belt retraction force is reduced,in particular, when the vehicle is stationary. Again, a check is made inadvance as to whether the respective safety belt has not already beendonned.

The opening of a vehicle door is identified as a further situation, andused to set the belt retraction force to a prescribed belt donningvalue. In particular, the belt retraction force is lowered to a level ofoperational convenience that supports the occupant when donning thebelt.

Moreover, the belt retraction force can be reduced to a prescribed beltdonning value upon detection of an occupant in a seat so as tofacilitate fastening. It is possible, therefore, to set the beltretraction force on the relevant safety belt in a way that is related toseating place and individual.

The belt retraction force is continuously or uniformly and slowly raisedto a prescribed belt donning value after termination of the fasteningoperation for the purpose of pleasant convenience in wearing the beltwhile driving. The locking of the belt lock, for example, is monitoredto this end. Thus, the belt slack can be present before or can beremoved as driving begins, such that the occupant is held sufficientlyby the safety belt.

In a further embodiment, it is possible to slowly raise the beltretraction force after termination of the fastening operation and expiryof a prescribed time or upon the reaching of a prescribed speed of thedriver's own vehicle. This also minimizes the belt slack by raising thebelt retraction force to a prescribed belt wearing level or to aprescribed force level. Alternatively, after the extension of the safetybelt to a prescribed maximum extension value and a following reductionin the belt extension to a prescribed belt donning value, the beltretraction force can be raised slowly and continuously in order tominimize the belt slack.

A slow continuous and markedly short rise in the belt retraction forceresults after termination of the fastening operation and expiry of aprescribed time or upon the reaching of a prescribed vehicle speed, inorder to effect the belt slack minimization quickly, for example giventhe presence of a high speed of the driver's own vehicle. Again, thebelt retraction force can be substantially raised given a seat occupancydetection identified outside the optimum position.

Furthermore, upon the vehicle engine being turned off, upon withdrawalof the ignition key or upon actuation of the belt lock in order tounfasten the safety belt, the belt retraction force is substantiallyraised to a prescribed value or a force level for assisting the takingoff of the safety belt. This enables a reliable retraction of the safetybelt.

In the event of the presence of a further situation, such as after thesafety belt has been taken off, after the reaching of a prescribedminimum belt length, after the locking of the vehicle, after an openingand closing of the vehicle door, or after expiry of a prescribed time,the belt retraction force is set from the wearing level to a prescribedoperating level. That is to say, the safety belt is appropriatelyloosened for good operational convenience such that the extension forceis reduced upon the next fastening, and the occupant is assisted whenpulling the safety belt.

In order to avoid the flapping of a safety belt that is not requiredduring driving, for example, in the event of uneven roads, the beltretraction force is set to a prescribed belt donning value, inparticular to a higher value relative to the operating level, for anunoccupied seat and for when the driver's own vehicle exhibits a certainspeed.

Again, during driving with an open folding roof or as a function of thevehicle speed, the belt retraction force is set for an unoccupied seatto a prescribed belt donning value and raised relative to the normaloperating level such that the belt is tensioned and a flapping of thebelt is prevented or at least reduced. It is also possible in this caseto set the belt retraction force as a function of speed.

In a further embodiment, given identification of a sport driving mode orof a winding drive, the belt retraction force is set in a fashionrelated to seat position, in particular being set differently andindividually for the driver and the remaining occupants. The differentperceptions by the driver and by another occupant are taken into accountin this case, and the safety belt is appropriately tensioned in a weakor strong fashion.

In order to improve the belt wearing comfort in critical situations, thebelt retraction force or the belt holding force is appropriately set oradapted before or during lateral accelerations and the safety belt isappropriately tensioned in relation to the situation.

The situation related settings of the belt retraction force, such as thesteering angle, the lateral acceleration, the yawing rate, the vehiclespeed or the road profile are determined with the aid of sensors or of anavigation system, for example with the aid of digital roadmaps, inorder to determine the situation. The measured values are fed to anevaluation unit for determining the operation or surrounding situationwith the aid of one of the operation, safety or convenience functions isset on the restraint or belt comfort system by virtue of the fact thatthe belt retraction force acting on the safety belt can be set via asetting device as a function of the situation determined. By way ofexample, the setting device for the belt tensioning mechanism isprovided by a conventional spring setting device for continuouslysetting a spring force on a restoring spring of the safety belt, or anelectric motor, connected to a winder shaft, for setting the belttension on the safety belt.

Other objects, advantages and novel features of the present inventionwill become apparent from the following detailed description of theinvention when considered in conjunction with the accompanying diagrams.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic of a device for control or regulation of arestraint system having a safety belt and an evaluation unit fordetermining an operating or surrounding situation and a setting devicefor setting at least one operation function on the restraint system, and

FIG. 2 shows a force-time diagram for illustrating the force profile foran improved belt operating and belt wearing convenience function.

Mutually corresponding parts are provided in both figures with the samereference symbols.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a device 1 for control or regulation of a restraint system2 (also termed belt comfort system) having a safety belt 3 that iscontrolled by means of a setting device 4.

The setting device 4 is a conventional setting device, for example aspring setting device having a restoring spring for the belt retractor,or a winder shaft for the belt retractor that is connected to anelectric motor.

An evaluation unit 5 for examining an operating or surrounding situationof the vehicle is provided in order to set the belt retraction force ina fashion related to the situation. Measured values M1 to Mn are fed tothe evaluation unit 5 by, for example, sensors or control devices orother vehicle systems (not illustrated). For example, the steeringangle, the lateral acceleration, the yawing rate, the speed of thedriver's own vehicle, the speed of a vehicle driving in front, theposition of an object lying ahead or the data of a digital roadmap andthus an item of information relating to the curve profile of the roadlying ahead are fed to the evaluation unit 5 as measured values M1 to Mnfor the purpose of determining a situation.

The acquired measured values M1 to Mn are used to control or regulatethe belt retraction force by means of the evaluation unit 5. In thisprocess, the retraction force, for example, is varied by controlling orregulating the belt retraction force in a fashion related to situation.

The operating convenience, the belt donning convenience and the beltfastening convenience are improved by reducing the belt retraction forcein relation to seating position for the respective safety belt 3 or, inrelation to the vehicle, for all safety belts 3. This is done in anumber of different situations including, upon unlocking the vehicle,upon opening the vehicle door, or upon detecting an occupant on a seat.

In a further exemplary embodiment, the belt retraction force is raisedto a belt wearing level or to a higher force level depending on thesituation, for example, in order to minimize the belt slack, afterfastening of the safety belt 3, after a specific time following thefastening, starting from a specific vehicle speed, after reversal of thedirection of rotation during retraction when fastening, or afterstarting the vehicle.

In addition, in further situations, for example after a specific time,the belt retraction force can be reduced to an optimum belt wearingcomfort level, or be reduced to an individual belt wearing level thatcan be set.

In order to set the comfort of the safety belt 3 during driving of thevehicle, the belt retraction force can be adapted or set depending onthe situation. The belt retraction force is raised such that the belt istensioned, for instance at relatively high speeds or for winding roads,such that the occupant is held more effectively. The belt retractionforce can be set individually for the driver or for an occupant, whenthe sport driving mode is set, or when driving with an open foldingroof. The belt retraction force can also be raised in order, forexample, to prevent or to reduce the flapping of the safety belt 3; orin order to enable the safety belt 3 to be reliably retracted.

Substantial raising of the belt retraction force, and thus a strongtensioning or retraction of the safety belt 3 is carried out uponturning off the engine, upon withdrawing the ignition key, uponunfastening the safety belt 3 in order to enable the safety belt 3 to bereliably retracted; in the event of an unoccupied seat, in order toavoid flapping in the event of uneven roads; or when the occupant bendsforward in order to be able to be held securely.

A reduction in the belt retraction force, for example from the safetycomfort level or wearing comfort level to an operational conveniencelevel results after taking off the safety belt 3. That is to say, theminimum belt length is reached after closing or locking the vehicle,after opening the door or closing it again, or after the expiry of along time.

Moreover, the belt retraction force can also be set and adapted with theaid of further situations that characterize the operating functions orthe surroundings of the vehicle in more detail, and are determined withthe aid of further measured values M1 to Mn. Adapting the beltretraction force in relation to situation improves the operationalconvenience, the wearing comfort or the safety comfort of the restraintsystem 2, in particular of the safety belt 3, for the occupant.

FIG. 2 shows a force-time diagram for representing a possible temporalprofile of the belt retraction force F for improved belt operating andbelt wearing comfort functions. The belt retraction force F can exhibita varied characteristic depending on stipulation and setting of the beltoperating and belt wearing comfort functions.

In step S1, the safety belt 3 is taken off in its storage position, andis held securely and firmly in the storage position with a prescribedbelt retraction force F. Inadvertent loosening of the safety belt 3 isavoided.

If, at the instant t1, the beginning of a fastening operation isdetected, for example the opening of a vehicle door, the operation ofthe central locking system, the belt retraction force F is lowered instep S2 to a prescribed, defined operator comfort force level. Thisgives rise at the safety belt 3 to a so-called belt slack thatfacilitates fastening for the occupant, and thus raises the operationalconvenience.

During the fastening operation, in step S3 the belt retraction force Fis held at the prescribed operational convenience force level. Once thebelt is locked and driving has begun, that is to say there is a vehiclespeed v of greater than 0, it is detected that the fastening operationis terminated (=instant t2).

In order to reduce the belt slack set in step S2, the belt retractionforce F is raised in step S4. The belt retraction force F is, forexample, between 10 N and 20 N and is, in particular, raisedcontinuously and quickly such that the safety belt 3 is tensioned. Thetensioning of the safety belt 3 is terminated once a prescribedthreshold value is reached or exceeded. Alternatively, the locking ofthe belt can terminate the operation of reducing the belt slack, andthus the tensioning of the safety belt 3.

The belt retraction force F is lowered to a prescribed wearing comfortlevel in step S5, for example continuously and quickly, for the purposeof a high level of wearing comfort of the safety belt 3 during driving.In the exemplary embodiment, the belt retraction force F has anapproximately identical operational convenience level and wearingcomfort level. Depending on stipulation and setting as well asfunctioning of the restraint system 2, the operational convenience levelcan be set at a higher or lower level than the wearing comfort level.

The set wearing comfort level is kept during driving—see step S6. If anunfastening operation is identified at an instant t3, for example theopening of the belt lock, the belt retraction force F is raised in orderto achieve a reliable retraction of the safety belt 3 into the storageposition. The retraction of the safety belt 3 is performed softly inthis case. The profile of the raising of the belt retraction force F isparameterized appropriately to this end.

If during driving, that is to say the wearing comfort level has been setand is active, a belt slack should arise in step S6. For example, if theoccupant bends forward briefly, the belt retraction force F is brieflyraised in accordance with step S4, in order to reduce the belt slack,and is lowered again in accordance with step S5, in order to set thewearing comfort level. The occurrence of the belt slack during drivingis detected with the aid of a suitable sensor system and means. The beltretraction force F is set in steps S4 and S5 with a characteristic thatis changed relative to the exemplary embodiment in order to tension thesafety belt 3 during driving.

In step S1, the safety belt 3 again lies in the storage position.

The foregoing disclosure has been set forth merely to illustrate theinvention and is not intended to be limiting. Since modifications of thedisclosed embodiments incorporating the spirit and substance of theinvention may occur to persons skilled in the art, the invention shouldbe construed to include everything within the scope of the appendedclaims and equivalents thereof.

The invention claimed is:
 1. A method for control or regulation of arestraint system in a vehicle, the method comprising: determining, by anevaluation unit, whether a situation exists; adjusting, by a settingdevice, a belt retraction force acting on a safety belt of the restraintsystem based on the determined situation, wherein the adjustment sets atleast one of an operation function of the restraint system that supportsan occupant of the vehicle when donning and taking off the safety beltand a convenience function that sets an individual wearing level of thesafety belt, and wherein the determined situation is operation of acentral locking system of the vehicle and the adjustment is reducing thebelt retraction force, the determined situation is driving with an openfolding roof and the adjustment is raising the belt retraction force, orthe determined situation is setting of a sports driving mode and theadjustment is setting the belt retraction force in relation to theoccupant's seating position within the vehicle.
 2. The method as claimedin claim 1, wherein the belt retraction force is set to a prescribedbelt donning value.
 3. The method as claimed in claim 1, wherein thebelt retraction force is reduced upon the opening of a vehicle door. 4.The method as claimed in claim 1, wherein the belt retraction force isreduced upon detection of an occupant of a seat in the vehicle.
 5. Themethod as claimed in claim 1, wherein the belt retraction force iscontinuously raised to a prescribed belt donning value after thetermination of at least one of a fastening operation, the expiration ofa prescribed time, or the reaching of a prescribed vehicle speed.
 6. Themethod as claimed in claim 1, wherein the belt retraction force iscontinuously raised to a prescribed maximum extension value after theextension of the safety belt, and to a prescribed belt donning valueafter a subsequent reduction in the belt extension.
 7. The method asclaimed in claim 1, wherein the belt retraction force is varied when anoccupant is detected outside the optimum position and the belt path hasnot reached its previous value.
 8. The method as claimed in claim 1,wherein the belt retraction force is raised to a prescribed value uponthe occurrence of at least one of the vehicle engine being turned off,the withdrawal of the ignition key, or upon actuation of the belt lock.9. The method as claimed in claim 1, wherein when the safety belt isremoved, the belt retraction force is set to a prescribed operatingforce level.
 10. The method as claimed in claim 1, wherein the beltretraction force is set to a prescribed belt donning value for anunoccupied seat.
 11. The method as claimed in claim 1, wherein the beltretraction force is raised during driving as a function of the vehiclespeed.
 12. The method as claimed in claim 1, wherein upon identificationof a winding drive, the belt retraction force is set in relation to anoccupant's seating position within the vehicle.
 13. The method asclaimed in claim 1, wherein the belt retraction force is set before orduring lateral accelerations related to a surrounding situation.
 14. Themethod as claimed in claim 13, wherein the surrounding situation isdetermined by at least one of a forward looking sensor system, radarsystem, image processing system, or IR sensor.
 15. The method as claimedin claim 1, wherein the belt retraction force is adapted to react to thevehicle speed, vehicle data or curve profile of the road, which aredetermined by at least one of a forward looking sensor system,navigation data or data of a digital road map.
 16. The method as claimedin claim 1, wherein at least one of a steering angle, a lateralacceleration, a yawing rate, a vehicle speed or a road profile aredetermined as measured values by at least one of a sensor or digitalroadmap to set the belt retraction force.
 17. A device for control orregulation of a restraint system of a vehicle, wherein the devicecomprises: a safety belt; an evaluation unit for determining whether asituation exists; and a setting device, wherein the setting deviceadjusts a belt retraction force on the safety belt based on thedetermined situation, wherein the adjustment sets at least one of anoperation function of the restraint system that supports an occupant ofthe vehicle when donning and taking off the safety belt and aconvenience function that sets an individual wearing level of the safetybelt, and wherein the determined situation is operation of a centrallocking system of the vehicle and the adjustment is reducing the beltretraction force, the determined situation is driving with an openfolding roof and the adjustment is raising the belt retraction force, orthe determined situation is setting of a sports driving mode and theadjustment is setting the belt retraction force in relation to theoccupant's seating position within the vehicle.